Subject: Re: bug#75594: 31.0.50; [FR]: Change equality test for Pcase non-linear patterns

From: Michael Heerdegen <[email-masked]>
Date: Sun, 19 Jan 2025 23:37:05 +0100

Eshel Yaron <[email-masked]> writes:

> > (with-equality-predicate ((foo . #'equal))
> >   `(,foo ,foo ,foo))
> > ?
>
> I'd rather not specify all affected variables explicitly, if that's what
> this syntax implies.  The most important use case is to convert entire
> pcase patterns to use equal semantics.  So transforming an arbitrary
> pcase pattern to one where all non-linear patterns use equal should be
> as simple as possible.

We could additionally support (with-equality-predicate #'equal ...)

> (Accordingly, I tend to "vote" for simply
> changing the semantics to use equal, so no transformation is needed.)

This would be a backward-incompatible change so it's probably not
eligible for voting.

Michael.